Known run flat devices are generally constituted by a support ring mounted with clearance around a wheel rim inside a tire cover. The ring is made of flexible material and comprises a single piece, and because of its width at its base it exerts a force that presses the tire cover against the rim. Use is sometimes made of rigid devices made up of a plurality of sectors that are fastened together in pairs.
Document EP-A-1 541 384 in the name of the Applicant presents a run flat device for a wheel assembly comprising a rim made up of a plurality of blocks, having a support ring for mounting around the rim and subdivided into at least two ring sectors, and means for locking the beads of the cover against the flanges of the rim for connecting the ring sectors to said beads in order to ensure that the wheel assembly can deliver drive in the event of pressure therein being reduced.